Anastomosis is the surgical joining of tissues of tubular structures having a lumen, such as blood vessels, to create communication between the lumina of the structures. Anastomoses are employed in, for example, vascular surgery, for the purpose of creating or restoring blood flow pathways. One example of this is coronary artery bypass surgery (CABG), a procedure designed to restore blood flow to portions of the heart whose blood supply has been reduced by occlusion or stenosis of at least one coronary artery.
One method for CABG involves harvesting a saphenous vein from the patient's body, or using an artificial conduit, and connecting the vein or conduit to the occluded or stenosed artery as a bypass graft from another artery, such as the aorta, downstream of the occlusion or stenosis. In this method, the bypass graft must be attached to the sides of existing arteries at both the proximal and distal ends of the graft by proximal and distal anastomoses.
An alternative method involves rerouting a less important artery from its normal location to another location downstream of the occlusion or stenosis. In this method, only a distal anastomosis between the distal end of the graft and the side of an existing artery may be required to complete the procedure.
One method for performing vascular anastomosis is by hand suturing. This is a time-consuming and difficult task requiring a high degree of surgical skill to perform successfully due to the considerable perfection, required to achieve reliable and consistent functionality. The procedure poses consequently a relatively high risk to the patient, because the overall outcome is so much dependent on this functionality. Not only does the surgeon have to provide a leak-free connection of vessels so small, that optical magnification is routinely used, but also the anastomosis must provide a smooth, open flow path for the blood. In this method, there is frequently a need for additional suturing of the anastomosis to close any leaks that are detected. Besides the required precision, the time-consuming nature of a hand-sutured anastomosis is of special concern.
Since in CABG, anastomoses have to be constructed on a constantly moving, extremely vital organ, the operative technique needs a careful setup. In the majority of cases, the patient is typically supported on cardiopulmonary bypass (CPB) for most of the surgical procedure. The heart can then be safely stopped by cross-clamping the aorta to isolate it from the systemic circulation and perfusing it with a cardioplegia solution in order to offer an immobile and stable area for precise suturing. CPB itself is a traumatic procedure that may result in post-surgical complications, which are, among others, related to CPB duration. In recent years, alternative techniques have been developed to completely avoid CPB, by hand-suturing anastomoses on the beating, working heart using epicardial stabilizers (as described, for example in U.S. Pat. No. 5,836,311) that immobilize only a small area of the heart. However, practice has shown that the delicate procedure of hand-suturing the anastomosis may become even more difficult under such conditions, thus potentially having a negative impact on overall quality, even in experienced hands. Therefore, it is desirable to reduce the complexity and duration of the procedure by expediting the anastomosis procedure without reducing the quality or effectiveness of the anastomosis.
In order to reduce the difficulty of creating a vascular anastomosis during CABG, it is desirable to provide a rapid means for making a reliable anastomosis between a bypass graft, vein or artery and the native blood vessel. A first approach to expediting and improving the anastomosis procedure is through the use of stapling technology. However, the instruments for stapling other organs are not easily adaptable for use in creating a vascular anastomosis, and the small size of coronary arteries raises additional technical difficulties. Various attempts have been made to provide such vascular stapling devices, such as in U.S. Pat. Nos. 4,350,160 and 5,234,447. Other approaches to this problem are found in, for example, U.S. Pat. Nos. 4,366,819; 4,368,736; 4,624,257; 4,917,090 and 4,917,091.
More recently, specialized devices for creating a vascular anastomosis have been described in, for example, U.S. Pat. Nos. 5,695,504; 6,074,416; 5,931,842; 5,976,178; 6,066,148; 5,833,698; 5,707,380; 6,485,496 and U.S. Patent Publication No. US2002/0183769.
There remains a need for an anastomosis device which performs a suitable vascular anastomosis in a reliable manner and as quickly as possible